Every year, significant quantities of combustion products, including coal combustion products, are produced, including various types of ash, such as bottom ash, boiler slag and fly ash. These products are considered waste products of coal burning power plants and the issue of how to recycle or otherwise dispose of these products has become a concern. While various methods have been attempted to recycle these materials, (such as using small amounts in concrete), the current applications using such ash are limited due to certain undesirable properties of the ash. Thus, despite years of effort in searching for viable uses of the ash, substantial amounts of the ash go unused and are transported to landfills. The amount of ash that must be transported and then put into such landfills is significant.
The inventors herein have recognized a new approach using ash in road stabilization that takes advantages of the properties of ash. In the new approach, the ash may be used to stabilize various types of road bases, including dirt/gravel roads and sand roads. In one example, a process for the stabilization of roadways uses a combination of ash and an emulsion. One example process comprises mixing 5% to 50% of dry fly ash per square yard and 0.5 gallons to 2.5 gallons per square yard of the emulsion to the same area. The emulsion may be either of a resin base or asphalt base. However, various other ratios may be used, and additional materials may be added to further improve the road stabilization.
In another example, a durable, stabilized road base is obtained using a process that uses the existing roadbed soils, tilling it to a depth of approximately 4-6 inches, blending in approximately 10-25% coal combustion fly ash, introducing a site specific quantity of an emulsion, then grading and roller compacting the materials. The resultant road base may be significantly more stable and stronger than previous methods of stabilizing the road base. Again, the road may be tilled to various other depths, and various ratios of ash and an emulsion may be used. Further, various types of post processing may be used in place of grading an roller compacting, or these acts may not be used, if desired.
Thus, in at least some of the approaches herein, ash that would otherwise be transported to landfills may be beneficially used to improve roadway construction. In some examples, the addition of ash provides for strengthened road bases, while reducing the amount of other more expensive materials that would otherwise be used to create the road base. Further, the ash can provide a stronger surface, without substantial disruption to the environment.
Various other examples are described herein.
Examples of dust suppressants and soil stabilizers are disclosed in U.S. Pat. Nos. 4,001,033; 4,571,116; 4,737,305; 4,801,635; 5,084,207; 5,412,007; and 5,824,725, the disclosures of which are incorporated by reference in their entirety for all purposes.
In another aspect of the disclosure, the inventors herein have found that a mixture of ash, and emulsion, and optionally mixed with soil may provide termite deterrence.